Ovens following the present invention and having linear sources of visible and infra-red radiant energy are disclosed and described in U.S. Pat. No. 5,036,179 and U.S. patent application Ser. No. 07/738,207 which are incorporated herein by reference. These ovens provide high-speed, high-quality cooking and baking of food items by impinging high-intensity visible, near-visible, and infrared radiations onto a food item. The ovens cook the food items within the short periods of time normally found in microwave cooking while maintaining the browning of infrared cooking and the quality of conduction-convection cooking. When food is exposed to a sufficiently intense source of visible, near-visible, and infrared radiation, the food absorbs low levels of visible and near-visible radiation, thereby allowing the energy to penetrate the foodstuff and heat it deeply. The longer infrared radiation does not penetrate deeply but acts as an effective browning agent.
Ordinarily, the source of the visible, near-visible and infrared radiation for this invention is in excess of two elongated quartz-halogen tungsten lamps, or equivalent means such as quartz arc lamps. Typical quartz-halogen lamps of this type operate at 3000 degrees Kelvin and convert electrical energy into black body radiation having a range of wavelengths from 0.4 .mu.m to 4.5 .mu.m with a peak intensity at 0.965 .mu.m. Each lamp can generally provide about between 1.5 and 2 kW of radiant energy with a significant portion of the energy in the visible light spectrum.
The ovens can use a plurality of these lamps or an array of several lamps either operated in unison or selectively operated in varying combinations as necessary for the particular food item sought to be cooked. These radiation sources are ordinarily positioned above and below the food item. The walls of the surrounding food chamber are preferably made from highly reflective surfaces. The visible and infrared waves from the radiation sources impinge directly on the food item and are also reflected off the reflected surfaces and onto the food item from many angles. This reflecting action improves uniformity of cooking.
Because of the great speed with which lightwave ovens are capable of cooking and the high intensity of the lamps used in lightwave cooking, great care must be taken to prevent overcooking of some or all areas of the food item. For example, the areas of the food item that are positioned directly above or below the radiation sources receive more direct energy and therefore cook more quickly than their surrounding areas, because the intensity of radiant energy received by an object decreases with the increase in distance between the object and the radiant energy source. It is therefore desirable to rotate the food relative to the lamps in order to distribute the light intensity more evenly over the food surface.
It is likewise desirable to remove a cooked food item from a lightwave oven soon after cooking, since even after the radiant energy sources have been turned off at the end of a cooking cycle, heat accumulating in the oven can cook the food by conduction and can thereby cook the food beyond the desired degree of "doneness."
Finally, given the substantially reduced cooking times that have been achieved using lightwave ovens, the food handling time has become one of the more substantial limiting factors in preparing cooked food items. An apparatus is therefore needed which reduces the amount of operator handling of the food. In particular, it is desireable to have automatic means for unloading the cooked food item from the oven and for delivering it onto a work surface.